package com.ad.pet.ui;

import android.content.Context;
import android.support.annotation.Nullable;
import android.support.v7.widget.RecyclerView;
import android.util.AttributeSet;
import android.view.MotionEvent;

import java.lang.ref.WeakReference;

/**
 * Created by SEELE on 2019/6/14.
 */

public class AutoPollRecyclerView extends RecyclerView {
    private static final long TIME_AUTO_POLL = 50;

    AutoPollTask autoPollTask;

    private boolean running; //标示是否正在自动轮询

    private boolean canRun;//标示是否可以自动轮询,可在不需要的是否置false


    public AutoPollRecyclerView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        autoPollTask = new AutoPollTask(this);
    }


    static class AutoPollTask implements Runnable {

        private final WeakReference<AutoPollRecyclerView> mReference;
        //使用弱引用持有外部类引用->防止内存泄漏


        public AutoPollTask(AutoPollRecyclerView reference) {
            this.mReference = new WeakReference<AutoPollRecyclerView>(reference);
        }

        @Override


        public void run() {
            AutoPollRecyclerView recyclerView = mReference.get();
            if (recyclerView != null && recyclerView.running && recyclerView.canRun) {
                recyclerView.scrollBy(2, 2);
                recyclerView.postDelayed(recyclerView.autoPollTask, recyclerView.TIME_AUTO_POLL);
            }
        }

    }
    //开启:如果正在运行,先停止->再开启


    public void start() {
        if (running)
            stop();
        canRun = true;
        running = true;
        postDelayed(autoPollTask, TIME_AUTO_POLL);
    }


    public void stop() {
        running = false;
        removeCallbacks(autoPollTask);
    }

    @Override


    public boolean onTouchEvent(MotionEvent e) {
        switch (e.getAction()) {
            case MotionEvent.ACTION_DOWN:
                if (running)
                    stop();
                break;
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL:
            case MotionEvent.ACTION_OUTSIDE:
                if (canRun)
                    start();
                break;
        }
        return super.onTouchEvent(e);//return false，注释掉onTouchEvent()方法里面的stop和start方法，则列表自动滚动且不可触摸
    }
}
